Dugdale (1971, 1988) applied Pasiphila to a group of New Zealand
species segregated from the old, broad concept of Chloroclystis: the
principal character noted was the occurrence of fasciculate antennae in the
male. Mironov (1990) transferred a number of Palaearctic species out of Chloroclystis
sensu lato into Rhinoprora, though Gymnodisca Warren has page
priority and is based on a Bornean species very similar in genitalic features to
the type species of Rhinoprora, also Bornean. Mironov did not consider Gymnodisca
as congeneric with Rhinoprora so the 'first reviser' principle
does not apply and the priority stands.

The principal question is whether Pasiphila and Gymnodisca/Rhinoprora
are congeneric. There are a number of features, mostly of the male
genitalia, that support this. Dugdale (1971) compared the New Zealand species
with the Palaearctic rectangulata Linnaeus, then considered to be the
type species of Chloroclystis. The features he noted as differing in male
and female genitalia need to be considered within the context both of Gymnodisca/Rhinoprora
and with relation to the general disintegration of Chloroclystis sensu
lato. Apart from the male antennae, he noted features of the anellus and
size of the vesica in the male and the insertion of the ductus seminalis in the
female. Additional features that appear to be informative are also in the male:
the condition of the octavals on the eighth sternite; the shape and setation of
the valves, particularly that of the sacculus; the cornuti in the vesica. The
condition of the signum of the female should also show some uniformity, as this
feature is used to distinguish several other eupitheciine genera.

The male antennae in Gymnodisca/Rhinoprora are filiform, smooth,
not strongly fasciculate as in Pasiphila. The ductus seminalis opens into
the bursa in both groups, rather than between the colliculum and ostium in the
ductus. The aedeagus vesica usually has two or more cornuti in both. Other
common features include: well-separated octavals, usually curved over the apical
part and separate apically from the main sternal sclerite; spined dorsal and
ventral manica pads on the anellus, the spines usually rather fine, not markedly
dissimilar in size in the New Zealand group, but tending to have a pair of
considerably more robust ones in the dorsal array in the other group, including
Palaearctic species such as rectangulata.

The valve structure is remarkably uniform, and provides a good
additional feature to define a broader concept for Pasiphila that
includes the northern hemisphere taxa. The shape is tongue-like, apically
rounded, the sides more or less parallel except for a slight bulge at the base
of the ventral margin, where the sacculus bears a group of prominent setal bases
that give rise to very long, hair-like setae. From this there extends up the
ventral margin a zone covering one quarter of the valve width where there is
fine horizontal pleating and sparse, irregularly placed setae. Dorsal to this is
a zone of much finer setae, densely packed and all running neatly parallel
towards the valve costa and extending slightly beyond it. There are no obvious
coremata or structures on the sternal membrane between the genitalia and the
eighth segment, but in Bornean species at least, there is a deciduous brush of
long scales longer than the valve arising at its basal margin exteriorly on the
intersegmental membrane. This is present but weak in New Zealand species, and
particularly well developed in P. eurystalides Prout comb. n.

The signum is usually a patch of scobination or absent: in the New
Zealand group the scobination is sometimes coarse on a small sclerotised plate,
with fields of lighter spines more distally.

The genus can probably be divided into a number of subgenera, the New
Zealand Pasiphila group with fasciculate male antennae being one.
Palaearctic and Oriental tropical species are referable to subgenus Gymnodisca
(= Rhinoprora), defined by presence of two enlarged, hornlike spines
on the dorsal manica and by variably elongated labial palps. A number of other
species may be referable to Pasiphila as defined here, but do not fall
readily into either of these subgenera, such as P. testulata Guenée
comb. n. (Australia, Norfolk I., New Zealand, Chatham Is., Kermadec Is.), the
related P. nina Robinson comb. n. (Fiji) and perhaps further Australian
and New Zealand species attributed to Chloroclystis by Dugdale (1988) and
Nielsen, Edwards & Rangsi (1996).

Prout (1932c) noted differences in the forewing venation amongst montane
Oriental taxa that he used to distinguish Gymnodisca and Rhinoprora as
subgenera of Chloroclystis, and discal lacunae in the forewings of male Gymnodisca
were noted in the original description of that genus. These may offer means
of recognising groupings within subgenus Gymnodisca or are autapomorphic
for individual taxa. The elongation of the labial palps is also variable.

There are nine species in Borneo, five endemic, all montane with strong
representation in the two highest zones of G. Kinabalu. The specimens referred
to Chloroclystis viridescens Warren by Prout (1932c) have not been
located and the species has not been recorded during the intensive montane
sampling of recent surveys: presence of this species in Borneo needs
confirmation, though it is also referable to Pasiphila [Gymnodisca] comb.
n.

The larvae of European species feed on the flowers of shrubs in Rosaceae
(rectangulata) and Encaceae (possibly the majority) in Britain and Japan,
where Theaceae are also involved (Allan, 1949; Sugi, 1987). There is a record
(IIE, unpublished) of viridescens feeding on Rhododendron (Ericaceae)
in New Guinea.